1. gets(0) quibble...
I'm still with 2.0 here, so again, it might have been fixed in 2.1...
Try the following program:
sequence File
procedure getPipe() -- Get input from pipe. e.g. dir | ex thiscode.ex
integer c
File = {}
c = gets(0)
while c >= 0 do
File = File & c
c = gets(0)
end while
end procedure
function input(sequence prompt)
sequence out
puts(1, prompt)
out = gets(0)
return out[1..length(out)-1]
end function
sequence name
getPipe()
name = input("What is your name?: ") -- Crashes here!!
The solution is to do this for input():
function input(sequence prompt)
sequence out
integer fh
puts(1, prompt)
fh = open("CON","r") -- The keyboard CONsole
out = gets(0)
close(fh)
return out[1..length(out)-1]
end function
Question: Which style of input() has Rob used in prompt_string() in the
new library files? Or does he avoid gets() altogether?
--
Carl R White -- Final Year Computer Science at the University of Bradford
E-mail........: cyrek- at -bigfoot.com -- Remove hyphens. Ta :)
URL...........: http://www.bigfoot.com/~cyrek/
Uncrackable...: "19.6A.23.38.52.73.45 25.31.1C 3C.53.44.39.58"
2. Re: gets(0) quibble...
in getPipe(), you need to use getc instead of gets.
EUPHORIA at LISTSERV.MUOHIO.EDU wrote:
> I'm still with 2.0 here, so again, it might have been fixed in 2.1...
> Try the following program:
>
> sequence File
>
> procedure getPipe() -- Get input from pipe. e.g. dir | ex thiscode.ex
> integer c
>
> File = {}
> c = gets(0)
>
> while c >= 0 do
> File = File & c
> c = gets(0)
> end while
> end procedure
>
> function input(sequence prompt)
> sequence out
>
> puts(1, prompt)
>
> out = gets(0)
> return out[1..length(out)-1]
> end function
>
> sequence name
>
> getPipe()
>
> name = input("What is your name?: ") -- Crashes here!!
>
> The solution is to do this for input():
>
> function input(sequence prompt)
> sequence out
> integer fh
>
> puts(1, prompt)
>
> fh = open("CON","r") -- The keyboard CONsole
> out = gets(0)
> close(fh)
> return out[1..length(out)-1]
> end function
>
> Question: Which style of input() has Rob used in prompt_string() in the
> new library files? Or does he avoid gets() altogether?
>
> --
> Carl R White -- Final Year Computer Science at the University of Bradford
> E-mail........: cyrek- at -bigfoot.com -- Remove hyphens. Ta :)
> URL...........: http://www.bigfoot.com/~cyrek/
> Uncrackable...: "19.6A.23.38.52.73.45 25.31.1C 3C.53.44.39.58"
--
Jeffrey Fielding
JJProg at cyberbury.net
http://members.tripod.com/~JJProg/
3. Re: gets(0) quibble...
- Posted by Ralf Nieuwenhuijsen <nieuwen at XS4ALL.NL>
Feb 16, 1999
-
Last edited Feb 17, 1999
>> Question: Which style of input() has Rob used in prompt_string() in the
>> new library files? Or does he avoid gets() altogether?
I consider this a bug and am assuming Robert will fix it. (btw: did you fix the
zero bug in puts ?)
Anyway, here is a working 'wrapped' version of gets ()
global function gets (integer fh)
sequence s
s = {getc(fh)}
while s[length(s)] != '\n' do
s = append(s, getc(fh))
end while
return s
end function
This will work.
Ralf Nieuwenhuijsen
.... Mailto://nieuwen at xs4all.nl
.... Http://www.xs4all.nl/~nieuwen
.... Uin://9289920
4. Re: gets(0) quibble...
On Tue, 16 Feb 1999, Jeffrey Fielding wrote:
] in getPipe(), you need to use getc instead of gets.
]
] EUPHORIA at LISTSERV.MUOHIO.EDU wrote:
]
] > I'm still with 2.0 here, so again, it might have been fixed in 2.1...
] > Try the following program:
] >
] > sequence File
] >
] > procedure getPipe() -- Get input from pipe. e.g. dir | ex thiscode.ex
] > integer c
] >
] > File = {}
] > c = gets(0)
] >
] > while c >= 0 do
] > File = File & c
] > c = gets(0)
] > end while
] > end procedure
Whoops. Coding on the fly from memory again... :-} One character changes
the whole semantics of the program. Story of my life ;) ZipDir, SPLIT,
GormLESS and GLess have all had bugs of this kind...
The bug is/was also apparent when using getc(0) (GormLESS uses gets(0)
and GLess uses getc(0) because of binary data).
I checked this behaviour out with Kelley & Pohl's "A Book on C" (which is
what Eu is written in), and it has something to do with the system setting
a flag when a file reaches an EOF marker. The flag only resets when the
file is closed. Since it's not possible to close the STD* files
(0, 1 and 2), the EOF flag isn't reset and usage of get*(0) for
keyboard input won't work after reading piped data.
There is a C function (according to the book) that resets the EOF flag
when *any* file is open, but this is probably unsafe, and it's probably
better to use the "CON" solution I proposed.
] > Question: Which style of input() has Rob used in prompt_string() in the
] > new library files? Or does he avoid gets() altogether?
No one answered this yet, and I still think it's a concern, albeit a very
tiny one :)
Carl
--
Carl R White -- Final Year Computer Science at the University of Bradford
E-mail........: cyrek- at -bigfoot.com -- Remove hyphens. Ta :)
URL...........: http://www.bigfoot.com/~cyrek/
Uncrackable...: "19.6A.23.38.52.73.45 25.31.1C 3C.53.44.39.58"
